Well-drilling equipment



D696. :16, 193@, R, ILKlNs WELL DRILLI NG EQUIPMENT Filed Feb. 11, 1928 2 Sheets-Sheet l W/IWVW M Z7 il INVENTOR. W? & BY v 5777 f jmml r A TTORNEYS.

Patented Dec. 16, 1930 PATENT OFFICE ROY WILKINS, OF SAN FRANCISCO, CALIFORNIA WELL-DRILLING EQUIPMENT Application filed February 11, 1928. Serial Io. 253306.

Another object of my invention is to pro-' vide means for accomplishing the above results which can be used in conjunction with standard equipment such as'is now used in drilling oil wells and be efiicient, practical and economical in its operation.

A further object of my invention is to provide a means for accomplishing the above results which is fully electrical in its operation whereby gears and other mechanical differential means are dispensed with.

Another object of my invention is to rovide means whereby the driving and fee ing of a drill by electrical means can be varied to produce a wide range of adjustment in the regulation of the drill feed.

A further object of m invention is to provide a driving and fee ing means for an oil well drilling tool employing a driving and a feeding motor whereb both the driving and feeding motor may lie employed for hoisting, so that the maximum capacity of both units will be available for this purpose.

It has long been recognized that the difliculties in rotar well drilling are most frequently caused by improper feed of the drill and various means have been pro osed for scientifically regulating the feed 0 the drill in proportion to the resistance it encounters.

It has also been recognized that if such a feed can be produced which will operate auto matically and independently of any personal equation, many of the accidents and errors due to incorrect drill feed will be eliminated and that the time re uired in drillin and the costs thereof will materially re need.

The most outstanding advance made toward the accomplishment of this result in recent years is disclosed by Frederic Waldorf Hild in his Netherlands Patent Number 12,- 915, issued April 15,1925. In this disclosure it is proposed to regulate the feed of the drill by employing the well known mechanical expedient of a differential gear drive. This is accomplished by connecting the driving motor to one half of the diiferential and to the rotary driving table; and connecting the feed regulating motor to the other half of the differential and the hoist drum to the central or floating part of the difl'erential so that the feed of the drill will be controlled by the differential of speed between the two motors, as determined by the load upon the driving motor,-which load will be determined by the nature of the earth being drilled.

This device has been found to operate very satisfactorily but it is open to the-objection that because of its complicated nature, it is expensive in both its first cost and in its maintenance cost.

In order to overcome these disadvantages and at the same time produce a device which will be more flexible than the above, I propose to dispense entirely with the difierential gear and take advantage of the inherent characteristics of induction motors by providing a specially constructed motor for gegllilating and controlling the feed of the For a better understandin of my invention, reference should be ha to the accompanying drawings, in which- Fig. 1 is a schematic diagram showing the essential parts of my invention and their relation to each other, I

Fig. 2 is a side elevation in section of an induction motor of special construction hav-' ing both its primary and secondary arranged so that they can rotate,

Fig. 3 is a plan view showin my device applied to a typical oil well dr lling equipment, and 95 Fig. 4 is an end view in section of the feed regulating motor, showing the provision'of a brake band surrounding the stator for holding it stationary when desired.

In order that a clearer understanding of my invention may be had, I have shown in Fig. 1 a schematic representation of an oil well drill equipped with the essential parts of my device and the necessary connections whereby the same is rotated and its feed controlled. I have also represented diagrammatically the external electrical circuits of the apparatus employed. In this figure of the drawings, 10 designates the stator of a dynamo electric machine having a rotor 11. The rotor 11 is mounted upon a shaft 12 which carries a pulley 13 from which power is transmitted to a rotary table 14 such 'as are common in well drilling equipment, by means of a belt or chain 15 .and in a manner to produce rotation of a drill 16. In addition to the aforesaid driving motor I also provide a specially constructed feed regulating motor which is mechanically connected to the driving motor. This regulating motor is of the induction motor type and has a rotor 17 and a stator 18, each of which is mounted so as to be-freely rotatable upon suitable bearings. The rotor 17 in the present instance is shown as mounted directly upon an extension of the shaft 12 so that it will rotate in unison with the rotor 11. It should be pointed out here, however, that the rotor 17 may be otherwise mechanically connectedwith the rotor 11, as by gearing; the only consideration here being that its speed bear a fixed relation to that of the rotor 11. It is conceivable that a difference in the relative speed of these two rotor elements may simplify or even eliminate the use of speed reducing means between the element 18 and the feed regulating device.

The stator 18 is provided with a quill shaft upon which it is mounted so as to be freely rotatable, as previously stated, with respect to its bearings. A pulley 19 which is adapted to transmit movement to a drill feed controlling device 20 by means of a belt or chain 22 is mounted upon the stator 18 so that any movement of the stator with respect t'o a previous stationary position will be transmitted to said feed regulating device to thereby raise or lower the drill as will hereinafter more fully appear.

The feed controlling device 20 is shown as a drum about which a hoisting cable 21 passes. This device 20 in an actual installation will be the main hoisting drum of a standard well drilling rig with the provision of clutches whereby it can be connected and disconnected to either the main driving motor when pulling the casing, etc., or to the regulating motor when the drill is in operation, as will be pointed out in connection with the description of Fig. 3 of the drawings.

When the above described power unit is placed in operation, current is supplied to the stator 10 from the power lines 23 through a suitable transformer 24:. A switch 25 in this circuit serves to connect the transformer 24 with the stator 10. The driving motor shown is of the wound rotor type of induction motor and it is provided with an external resistance 26 which is connected in the rotor circuit by means of brushes 27 and collector rings 28 so that the speed and torque characteristics thereof. can be controlled. The power lines 23 also supply power to the regulating motor through a suitable transformer 29 which is connected thereto by means of 'a switch 30. The switch 30 in this case is connected to the stator winding of this motor by means of brushes 31 and collector rings 32. The rotor 17 of this motor is of a type similar to that of the main driving motor and it too is provided with an external resistance 33 connected in its rotor circuit by means of brushes 34 and collector rings 35 so that the torque exerted between the rotor 17 and the stator 18 may be controlled.

In referring to the regulating motor as having a stator 18, it should be pointed out that this term is not used in the sense that the stator 18 is necessarily a stationary element. It is referred to as a stator in the sense that this element corresponds to the stator of a standard motor ofthe type used.

F or'a more detailed description of my improved regulating motor, reference should be had to Fig. 2 of the drawings. In this figure of the drawings it will be seen that the so-called stator element 18 is provided with extending quill shafts 40 and 41 which extend over the shaft 12 and engage suitable bearings so that it will be rotatably supported thereby. The quill shaft 40 also provides a mounting for the sprocket 19 over which the belt or chain 22 passes. It also carries the three collector rings 32 by means of which power is transmitted to the element 18.

Electrical apparatus of this construction has been constructed in the past and its operation is so well known that a detailed description thereof is thought not necessary. It will be sufficient for the purpose of this dis-- closure if it is understood that when the rotor element 17 is rotated at a speed in synchronism with that of the rotating magnetic field of the statorelement 18, the latter element will remain stationary and that if the rotor elements speed falls below this synchronous speed, the stator element 18 will tend to rotate in the opposite direction to thereby maintain a relative speed between these two elements, which speed will be the synchronous speed of such a motor less its slip. The slip in this case will be determined by the load imposed upon the element 18 by means of the belt or chain 22 as will hereinafter appear. It should also be mentioned that by the provision of external resistance in the circuit of the rotor element 17, I have provided means whereby the torque and there- .companies. The disclosure of this figure is substantially the same as that of Fig. 1 with the exception that an attem t has been made to illustrate a practical em odiment of my invention showing apparatus suitable for carrying out the operations sought. The main driving motor and the regulating motor in this figure areshown as connected upon the common shaft 12 and a gear element consisting of a pinion 42 upon the shaft 12 and a gear 43 is provided in the drivin connection between the drilling rig and the power unit. The drilling ri comprises a suitable foundation 44 upon w ich suitable bearings are provided for a countershaft 45, a drill r0 tating shaft 46 and the hoisting drum 20. A second foundation 47 is also located in alignment with the shaft 46 upon which the rota-t able table 14, throu h which the drill 16 passes, is mounted. he countershaft is provided with a sprocket 48 through which it receives power fromthe main driving unit by means of a chain 49. It also carries additional sprockets 50 and 51 which function to transmit power from the countershaft 45t0' the hoisting drum 20 and the'drill shaft reiii".

spectively by means of chains 52 and 53. The chains 52 and 53 cooperate with sprockets 54 and 55. The sprocket 55 is mounted upon a stub shaft 56 which is connected by beveled" gears 57 to the drill rotating shaft 46 and the sprocket 54 is provided with clutch engaging lugs which cooperate with a clutch member 58 so that when the two are-engaged the power of the main driving motor can be employed in rotatingthe drum 20 when the same is used in a hoisting operation such as in pulling the well I casing, etc. A similar clutch element 59 is also provided at the o posite end of the drum 20 which operates in conjunction with a sprocket 60. The sprocket (30 is connected with the statorelement of the regulating motor by means of the chain 22. \Vhen the clutch 59 is engaged the regulating motor will be connected to the drum 20 so that it will be operated in a manner to control the feed of the drill. The shaft 45 is shown as having gypsies 61 mounted on the ends thereof so that various pulling opera tions can be carried out independently of the hoisting drum. Brake bands 62 are also shown in connection with the hoisting drum 20, as is customary in a rig of this type. The rotary table 14 is provided with a beveled gear upon its underside which meshes with a beveled pinion 63 carried upon the outer end of the shaft 46 and provides a driving connection through which the table is driven.

F mm the above it will be evident that the construction of my regulating motor as described to this oint will not permit its being utilized in the oisting operation and I have therefore provided an additional feature whereby the power can be applied to the drum 20 during the hoisting and easing pulling operation. This feature isillustrated in Fig. 4 of the drawings. It consistsin providing a band 65 which can be contracted about the stator element 18 by means of a. hand wheel 66 so as to secure the same firmly to its base. It will be seen that when the stator 18 is so secured to its base, it Will operate as a standard induction motor and by reason of its connection with the driving motor as shown, its power can also be applied through the gears 42 and 43 to the counters'haft 45 and thence to the drum 20. In the event that a band 65 is provided it is to be understood that the clutch 59 will be disengagedv from the pinion 60 so that the drum shaft can rotate freely therein.

An alternative for this method of securing the stator element 18 stationary might be effected by providing a means of securm the pinion 6 0 stationary with respect to the rilling rig foundation 44.v If th s were done, the

chain 22 would serve in the same manner as the band 65 to hold the stator element 18 stationary.

Before proceeding with a description of the operation of my invention some consideration should be given the characteristics of the feed regulating means which I propose to employ. It is well known that the speed of the rotor of an induction motor is less than the synchronous speed of the rotatingmagneticfield by an amount equal to. the slip of the rotor. It is also well known that this slip is dependent upon the tor ue being transmitted and the resistance of t e rotor or secondary circuit. .It will also be evident in the, case of a motor constructed as is my so-called feed regulating motor, i. e., with rotatable stator or primary and rotatable rotor or secondary elements, that a torque will be exerted beween them which will'tend to cause them to rotate in opposite directions with respect to each other at a relative speed equal to the normal speed of the motor, should one of the parts be held stationary and that,

therefore, if the stator 18 is connected to a suitable load, which load in the present instance is the feeding mechanism 20, it will exert a torque thereupon tending to lift or counterbalance the weight of the drill 16.

, With the above in mind, reference should be had again to Fig. 1 of the drawings. In connection with this figure I shall first describe the fundamental operating principles of my device and then proceed with a detailed description in connection with Fig. 3. It is assumed that the switch 25 is closed and that the resistance 26 of the main motor has been properly adjusted and that the rotor 11 is turning in the direction indicated by the arrow thereon. This will cause the belt or chain 15 to move as indicated by arrows adjacent thereto and rotate the table in a. clockwise direction as indicated so that the drill will be given a right hand twist in the hole being drilled. Under these conditions the rotor 17 will also rotate in the same direction as the rotor 11 and when the switch 30 is closed so as to energize the stator element 18,

a torque will be produced between the rotor.

17 and the stator element 18 tending to rotate the stator 18 in a direction indicated by the arrow thereon. This torque is due to the fact that, as previously stated, the stator element 18 will in its endeavor to maintain a relative speed equal to its normal speed between itself and the rotor 17, tend to rotate in a di- 'rection opposite to that of the rotor 17 and since the speed of the rotor 17 is always the same as that of the driving motor rotor 11, it will be seen that this torque will change from time to time as the main or driving motor speed changes. It should be noted here that the torque exerted between these elements' 17 and 18 is the greatest when the slip therebetween is the highest. It should also be noted that this slip increases as the speed of the rotor "17 decreases and since this decrease in speed is the direct result of the load created by the drill, which load is determined to a large degree b the pressure of the drill on the bottom of t e hole, the torque will be substantially proportional to the pressure of I the drill upon the bottom of the hole and therefore by mechanically applying this torque as proposed by me, itis posslble to counterbalance the weight of the drill by this torque and thus regulate the pressure upon the drill to any value desired. In the present embodiment, this torque is transmitted from the pulley 19 through the belt or chain 22 to the drum 20 and tends to rotate the drum 20 in a direction suitable to wind the cable 21 thereon and when the torque producedbetween the rotor 17 and the stator element 18 is suflicient to overcome the weight ofthe drill 16 the drum 20 will be turned and the drill raised out of the hole. If the torque existing between the rotdr 17 and the stator element 18 is not sufficient to lift the drill 16, and the drill as a result, exerts too much downward pressure within the hole it will be possible to increase the above torque by changing the resistance 33 to a value which will produce the proper torque and by this means it will be possible to so control the torque of the regulating motor that practically any degree of pressure upon the drill may be produced Within wide limits.

By referring to Fig. 3 it will be seen that the above described operation can be admirably carried out with the standard form of drilling rig by simplyproviding means for connecting the stator element 18 to the usual hoisting drum. This means, in the present instance, is the clutch 59 and sprocket 60 in cooperation with the chain 22. When a rig of this type is used, power will be transmitte from the driving motor to the countershaft 45 by means of the gears 42, 43 and the chain 49, If the countershaft 45 is rotating it will be evident that power will be transmitted from this shaft through the chain 53 to the shafts 56 and 46 and thence to the drill table 14 so as to rotate the drill 16. If it is desired, a clutch may be provided between the shaft 45 and the sprocket 51 so that the drill driving elements may be stopped if desired during the hoistin operation. If it is desired to use the mam driving motor in hoisting, as when pulling the casing from the well, etc., this can be done by engaging the clutch 54 with the drum. Under these conditions power will be transmitted to the drum 20 through the chain 52 and the clutch 54. During this operation the clutch 59 may be left engaged or it may be disengaged, as desired, and since no detrimental result is obtained, it no doubt will be left in the engaging position. The regulating motor under these conditions will'exert torque tending to assist the main motor but this torque, of course, will be only a small fraction of its total capacity. It will be possible, however, to utilize the full capacity of both motors during the hoisting operation if a need for this additional power is present. This may be done by the application of the additional feature which is illustrated in Fig. 4 of the drawings. This feature comprises the addition of a band which surrounds the stator element 18 so that when it is applied thereto the stator element 18 will be held stationary. When this feature of my invention is applied, the clutch 59 will be disengaged and the torque exerted by the regulating motor will then be transmitted through the shaft 12 to the ears 42 and 43 where it will combine with t e torque of the main motor and be applied to the hoisting operation.

From the above it will be seen that I have provided a driving unit for well drillin equipment which is new, novel, efi'ective an one which possesses many advantages not found in devices heretofore proposed for accomplishing the above results.

While I have shown the preferred form of my invention as now known tome, it is to be understood that various changes may be made in its construction without de arting from the spirit of the invention as defined in the ap nded claims.

Having thus described my invention, what I claim and'desire to secure by Letters Patent is:

1. A motive power unit for driving a cutting tool comprising a main driving motor, a cutting tool adapte to be driven by said motor, a means for controlling the feed of the whereby the stator of said second motor can rotate with respect to its rotor to thereby control the feed controlling means of said cutting tool.

2. An electro-mechanical motive power unit for driving and feeding a drill comprising a main motor for driving the drill, a means for controlling the feed of the drill, an auxiliary motor for driving the feed controlling means of said drill, the rotor of said auxiliary motor being mechanically connected with the rotor of said main motor and having its stator mounted to freely rotate about its rotor and connected with the feed controlling means for said drill whereby the feed of the drill will be determined by the speed of said driving motor.

3. A motive power unit for driving drills and the like, comprising a pair of inductionmotors having their rotors mounted upon a common shaft, one of said motors having its stator mounted upon said shaft so as to freely rotate about its rotor, means for transmitting power from said shaft to said drill whereby the same will be turned, a feed controlling device for the drill and means connecting the rotatable stator of one of said motors with the drill feed controllin device whereby the feed of said drill will e regulated.

4;. In an electro-magnetic motive power unit for driving well drilling equipment and the like, a main driving motor for rotating the drill, a second motor of the induction type having its rotor directly connected to said main motor, means whereby the stator of said second motor may rotate about its rotor, and means operated by the movement of said stator for controlling the feed of the drill.

5. an electi e-magnetic motive power unit for driving well drilling equipment and the like, the combination of a main driving motor for rotating the drill, a drill feed determining means, and an electro-magnetic differential means comprising an induction motor having its primary and secondary windings mounted rotatably and mechanically cor cted with said driving motor the dri eding means whereby the feed said dril determined by the speed of sait driving rotor.

tive power unit rm driving well d the lilac, the cot loin ties. are power device tor he as for controlling the as for driving the teed oil the drill co. n table electro-magnetic chanically connected to and rotatable with said motive ower device and the other with the drill feed controlling means, whereby the' drill will be raised and lowered in response to changes in the speed of said motive power, device.

7. In a motive power unit for driving well drilling equipment and the like, the combination of a motive power device for rotating the drill, means for driving the feed of the drill, a means for controlling the means for driving the feed of the drill comprising an induction motor unit having rotatable primary and secondary elements, means for mechanically connecting one of said rotatable elements with said motive power device whereby it will rotate therewith, and means connecting the other oi said elements with a drill feed controlling device whereby the slip between said elements will determine the feed of said drill 8. In a motive power unit for driving well drilling equipment and the like, the combination of a motive power device for rotating the drill. means for determining the feed of the drill, a means for controlling the means for determining the feed of the drill comprising an induction motor unit having rotatable primary and secondary elements, means for mechanically connecting one of said rotatable elements with said motive power device whereby it will rotate therewith, means connecting the other of said elements with a drill teed determining device so that the slip between said elements will determine the :teed of said drill, and means whereby the slip be tween said elements may be varied.

9. in a motive power unit for well drilling rigs and the like, the combination of a main power unit for operating the drill, a mechanism for controlling the feed oi the drill, and an induction motor element mechanically connected to said main power unit having means whereby it will operate to drive the drill feed controlling mechanism when said main power unit is operating and operate to hoist the drill'when said main power unit is stationary.

10. lln an electromagnetic motive power well. drillin equipment and a n driving motor r rotating operating the hoist, a drill iced i a second of the inype having rotor direct y cono. actor, sup"or""e i? second motor rotor d supports to control the controlling means, as

' n ay be lied llld

trolling means, and & gearless electro-inag netic differential means mechanically connected between said driving motor and the drill feed controlling means whereby the feed of said drill is determined by the speed of said driving motor.

12. in a motive power unit for drill drivingz, hoisting, and regulating, the combination of a main driving motor, a drill feed controlling means, a second motor mechanically connected to said main motor for driving the drill feed controlling means, means operated by said main motor for hoisting, and means whereby the torque of said second motor can be applied when desired with the torque of said main motor in hoistin R Y WILKILNS.

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